Influence of vegetation cover on thermal regime of mountainous catchments

Biologia ◽  
2006 ◽  
Vol 61 (19) ◽  
Author(s):  
Miroslav Tesař ◽  
Miloslav Šír ◽  
L’ubomír Lichner ◽  
Eva Zelenková
Keyword(s):  
Air Temperature ◽  
Plant Cover ◽  
Soil Surface ◽  
Growing Season ◽  
Water Shortage ◽  
Daily Maximum ◽  
Spruce Forest ◽  
Mean Values ◽  
Vegetation Height ◽  
Air Temperatures

AbstractAir temperature at heights of 5 and 200 cm above soil surface, as well as soil temperature at depths of 15, 30 and 60 cm were studied in the cold climatic zone at three localities (catchments) under different plant cover during the growing season of 2002. The catchments Kout (dead forest), Doupě (clearing) and Stolec (mature spruce forest) are situated in the National Park of the Šumava Mts. (Czech Republic) in elevation of 1105–1330 m a.s.l., in which Kout and Doupě form some small “islands” inside an extensive spruce forest. Plant transpiration was not limited by water shortage in all the three localities. It was found that both soil and air temperatures were influenced with plant cover. In hot and dry days, the extremes in daily and night air temperatures were a function of transpiring vegetation height, with higher daily maximum and lower night minimum for smaller vegetation. For the whole growing season (from 29 July to 10 October 2002), the mean values of air temperature were independent upon the plant cover, but the magnitude of the dispersion variance followed the sequence in ascending order: mature forest-clearing-dead forest.

scholarly journals Thermal growing season in Poland calculated by two different methods

2015 ◽  
Vol 47 (3) ◽  
pp. 261-273 ◽  
Author(s):  
Małgorzata Kępińska-Kasprzak ◽  
Przemysław Mager
Keyword(s):  
Air Temperature ◽  
Graphical Method ◽  
Growing Season ◽  
Threshold Value ◽  
Mean Values ◽  
Temperature Changes ◽  
Growing Seasons ◽  
Air Temperatures ◽  
Weather Stations ◽  
Comparative Results

Abstract Methods of identifying dates of passing determined threshold value are of significant importance in the study of thermal growing seasons. The difficulty to determine dates of beginning and end of growing season in a given year stems from the fact that daily mean air temperature changes irregularly on a day-to-day basis often crossing the threshold value (i.e. 5°C) multiple times. The most frequently used method to identify dates of threshold value crossing is the mathematical or graphical method proposed by Gumiński in 1950 which based on monthly mean air temperature values. In the 1970s, Huculak and Makowiec presented a method using daily mean values of air temperature. It is assumed that both methods give comparative results although calculations of daily mean air temperature render more accurate results. This paper presents the comparison of these two methods. Air temperatures measurements from 1966–2005 taken at 38 weather stations located in various physiographic conditions in Poland were used.

scholarly journals Seasonal dynamics of methane emissions from a subarctic fen in the Hudson Bay Lowlands

2013 ◽  
Vol 10 (7) ◽  
pp. 4465-4479 ◽  
Author(s):  
K. L. Hanis ◽  
M. Tenuta ◽  
B. D. Amiro ◽  
T. N. Papakyriakou
Keyword(s):  
Soil Temperature ◽  
Air Temperature ◽  
Growing Season ◽  
Near Surface ◽  
Growing Seasons ◽  
Air Temperatures ◽  
Soil Temperatures ◽  
Surface Soil Temperature ◽  
Filling Method ◽  
Highly Correlated

Abstract. Ecosystem-scale methane (CH4) flux (FCH4) over a subarctic fen at Churchill, Manitoba, Canada was measured to understand the magnitude of emissions during spring and fall shoulder seasons, and the growing season in relation to physical and biological conditions. FCH4 was measured using eddy covariance with a closed-path analyser in four years (2008–2011). Cumulative measured annual FCH4 (shoulder plus growing seasons) ranged from 3.0 to 9.6 g CH4 m−2 yr−1 among the four study years, with a mean of 6.5 to 7.1 g CH4 m−2 yr−1 depending upon gap-filling method. Soil temperatures to depths of 50 cm and air temperature were highly correlated with FCH4, with near-surface soil temperature at 5 cm most correlated across spring, fall, and the shoulder and growing seasons. The response of FCH4 to soil temperature at the 5 cm depth and air temperature was more than double in spring to that of fall. Emission episodes were generally not observed during spring thaw. Growing season emissions also depended upon soil and air temperatures but the water table also exerted influence, with FCH4 highest when water was 2–13 cm below and lowest when it was at or above the mean peat surface.

scholarly journals Pan-Arctic linkages between snow accumulation and growing-season air temperature, soil moisture and vegetation

2013 ◽  
Vol 10 (11) ◽  
pp. 7575-7597 ◽  
Author(s):  
K. A. Luus ◽  
Y. Gel ◽  
J. C. Lin ◽  
R. E. J. Kelly ◽  
C. R. Duguay
Keyword(s):  
Soil Moisture ◽  
Air Temperature ◽  
Land Surface ◽  
Regional Scale ◽  
Surface Characteristics ◽  
Growing Season ◽  
Snow Accumulation ◽  
Snow Season ◽  
Air Temperatures ◽  
Land Surface Characteristics

Abstract. Arctic field studies have indicated that the air temperature, soil moisture and vegetation at a site influence the quantity of snow accumulated, and that snow accumulation can alter growing-season soil moisture and vegetation. Climate change is predicted to bring about warmer air temperatures, greater snow accumulation and northward movements of the shrub and tree lines. Understanding the responses of northern environments to changes in snow and growing-season land surface characteristics requires: (1) insights into the present-day linkages between snow and growing-season land surface characteristics; and (2) the ability to continue to monitor these associations over time across the vast pan-Arctic. The objective of this study was therefore to examine the pan-Arctic (north of 60° N) linkages between two temporally distinct data products created from AMSR-E satellite passive microwave observations: GlobSnow snow water equivalent (SWE), and NTSG growing-season AMSR-E Land Parameters (air temperature, soil moisture and vegetation transmissivity). Due to the complex and interconnected nature of processes determining snow and growing-season land surface characteristics, these associations were analyzed using the modern nonparametric technique of alternating conditional expectations (ACE), as this approach does not impose a predefined analytic form. Findings indicate that regions with lower vegetation transmissivity (more biomass) at the start and end of the growing season tend to accumulate less snow at the start and end of the snow season, possibly due to interception and sublimation. Warmer air temperatures at the start and end of the growing season were associated with diminished snow accumulation at the start and end of the snow season. High latitude sites with warmer mean annual growing-season temperatures tended to accumulate more snow, probably due to the greater availability of water vapor for snow season precipitation at warmer locations. Regions with drier soils preceding snow onset tended to accumulate greater quantities of snow, likely because drier soils freeze faster and more thoroughly than wetter soils. Understanding and continuing to monitor these linkages at the regional scale using the ACE approach can allow insights to be gained into the complex response of Arctic ecosystems to climate-driven shifts in air temperature, vegetation, soil moisture and snow accumulation.

The Incidence of Climatic Conditions Favourable to Coffee Berry Disease in Kenya

1971 ◽  
Vol 7 (4) ◽  
pp. 303-314 ◽  
Author(s):  
J. M. Waller
Keyword(s):  
Air Temperature ◽  
Spore Germination ◽  
Growing Season ◽  
Climatic Conditions ◽  
Tree Canopy ◽  
Disease Development ◽  
Spore Dispersal ◽  
Coffee Berry ◽  
Coffee Berry Disease ◽  
Air Temperatures

SUMMARYClimatic conditions affecting the development of CBD are assessed by measuring wetness within the tree canopy and air temperature. Saturation of the tree canopy, necessary for spore dispersal, occurs most frequently at the tops of trees and the duration of wetness permitting spore germination is most prolonged at night. Night air temperatures are closest to berry temperatures and are important in assessing infection periods. Disease development in 1968 and 1969 was related to the number of infection periods during the growing season. Polythene tree covers which kept trees sufficiently dry to stop disease development were used in determining infection at different times of the year.

Efficiency of Grasshopper Baits in Relation to Time of Day of Application

1952 ◽  
Vol 84 (5) ◽  
pp. 147-155 ◽  
Author(s):  
R. H. Handford ◽  
L. G. Putnam
Keyword(s):  
Experimental Data ◽  
Surface Temperature ◽  
Air Temperature ◽  
Soil Surface ◽  
Time Of Day ◽  
Rapid Decrease ◽  
The Other ◽  
Feeding Period ◽  
Air Temperatures ◽  
Soil Surface Temperature

Literature on grasshopper control published hetween 1930 and 1942 stressed the desirability of applying poisoned bait when grasshoppers begin their first main feeding period of the day. Such pubiications include those by Parker (1930). Parker, Walton, and Shotwell (1932), Criddle (1932). Ruggles and Aamodt (1938), and Bird (1940). Parker (1930) found that the lesser migratory grasshopper, Melanoplus mexicanus mexicanus (Sauss.), fed sparingly on baits at air temperatures between 55°F. and 63°F., more actively between 64°F. and 67°F., and most actively between 68°F. and 78°F. A rapid decrease in feeding occurred when air temperature rose above 80°F. or the soil surface temperature above 113°F. Much the same relationship held also for the clear-winged grasshopper, Cammula pellucida (Scudd.). On the basis of such observations it was decided chat an air temperature of 68°F. might be classed as optimum for beginning the application of bait. Parker did not, however, indicate the degree of mortality resulting from such feeding; the other writers gave no experimental data.

scholarly journals The Impact of Site Extremes on the Onset of Phenological Phases of Selected Tree Species

2014 ◽  
Vol 62 (5) ◽  
pp. 1117-1124
Author(s):  
Jana Škvareninová
Keyword(s):  
Air Temperature ◽  
Tree Species ◽  
Soil Depth ◽  
Average Length ◽  
Growing Season ◽  
Corylus Avellana ◽  
Extreme Conditions ◽  
Air Temperatures ◽  
The Impact ◽  
Phenological Phases

In the years 2007–2013 we performed phenological observations of common hazel (Corylus avellana L.), blackthorn (Prunus spinosa L.), and hawthorn (Crataegus oxyacantha L.) at two locations of central Slovakia situated at elevations of 300 m and 530 m a.s.l. The phenophase of first leaves of all tree species started in the second half of April on average, and was conditioned by the average daily air temperatures above 0 °C. The earliest onset was observed at both locations in 2007 due to the highest average air temperature during the observed period, which in March reached the value of 6.1 °C. Colouring of leaves started in the second and third decades of September. Both phenophases began earlier at the location situated at the higher elevation due to the effect of aspect, terrain, and soil depth. During the last 7 years, the average length of the growing season of tree species situated at an elevation of 300 m was from 136 to 152 days, in more extreme conditions at an elevation of 530 m the growing season was shorter by 12 days in the case of blackthorn and by 5 days in the case of hawthorn.

scholarly journals Analyses of the Zagreb Grič observatory air temperatures indices for the period 1881 to 2017

2018 ◽  
pp. 67-85 ◽  
Author(s):  
Ognjen Bonacci ◽  
Tanja Roje Bonacci
Keyword(s):  
Time Series ◽  
Air Temperature ◽  
Partial Sums ◽  
Daily Maximum ◽  
Absolute Maximum ◽  
Absolute Minimum ◽  
Air Temperatures ◽  
Temperature Regimes ◽  
Urban Heat ◽  
Maximum Temperatures

The paper studies time series of characteristic (minimum, mean, and maximum) daily, monthly, and yearly air temperatures measured at the Zagreb Grič Observatory in the period from 1 Jan. 1881 to 31 Dec. 2017. The following five air temperatures indices (ATI) are analysed: (1) absolute minimum yearly, monthly, and daily; (2) mean yearly, monthly, and daily minimum; (3) average mean yearly, monthly, and daily; (4) mean yearly, monthly, and daily maximum; (5) absolute maximum yearly, monthly, and daily. Methods of Rescaled Adjusted Partial Sums (RAPS), regression and correlation analyses, F-tests, and t-tests are used in order to describe changes in air temperature regimes over 137 years. Using the RAPS method the five analysed yearly ATI time series durations of 137 years were divided into two sub-periods. The analyses made in this paper showed that warming of minimum air temperatures started in 1970, mean air temperatures in 1988, and maximum air temperatures in 1998. Results of t-tests show an extreme statistically significant jump in the average air-temperature values in the second (recent time) sub-periods. Results of the t-tests of monthly temperatures show statistically significant differences between practically all five pairs (except in two cases) of analysed monthly ATI subseries for the period from January to August. From September to December the differences for most of pairs (except in six cases) of the analysed monthly ATI subseries are not statistically significant. It can be concluded that the urban heat island influenced the increase in recent temperatures more strongly than global warming. It seems that urbanisation firstly and chiefly influenced the minimum temperatures, as well as that Zagreb’s urbanisation had a bigger impact on minimum temperatures than on maximums. Increasing trend in time series of maximum temperatures started 20 years later.

scholarly journals Field Measurements and Satellite Remote Sensing of Daily Soil Surface Temperature Variations in the Lower Colorado Desert of California

Climate ◽  
2018 ◽  
Vol 6 (4) ◽  
pp. 94 ◽  
Author(s):  
Dana Coppernoll-Houston ◽  
Christopher Potter
Keyword(s):  
Surface Temperature ◽  
Air Temperature ◽  
Land Surface ◽  
Population Biology ◽  
Soil Surface ◽  
Field Measurements ◽  
Ecosystem Change ◽  
Colorado Desert ◽  
Air Temperatures ◽  
Landsat Satellite

The purpose of this study was to better understand the relationships between diurnal variations of air temperature measured hourly at the soil surface, compared with the thermal infra-red (TIR) emission properties of soil surfaces located in the Lower Colorado Desert of California, eastern Riverside County. Fifty air temperature loggers were deployed in January of 2017 on wooden stakes that were driven into the sandy or rocky desert soils at both Ford Dry Lake and the southern McCoy Mountains wash. The land surface temperature (LST) derived from Landsat satellite images was compared to measured air temperatures at 1 m and at the soil surface on 14 separate dates, until mid-September, 2017. Results showed that it is feasible to derive estimated temperatures at the soil surface from hourly air temperatures, recorded at 1 m above the surface (ambient). The study further correlated Landsat LST closely with site measurements of air and surface temperatures in these solar energy development zones of southern California, allowing inter-conversion with ground-based measurements for use in ecosystem change and animal population biology studies.

scholarly journals Long-Term Winter Inversion Properties in a Mountain Valley of the Western United States and Implications on Air Quality

2015 ◽  
Vol 54 (12) ◽  
pp. 2339-2352 ◽  
Author(s):  
S.-Y. Simon Wang ◽  
Lawrence E. Hipps ◽  
Oi-Yu Chung ◽  
Robert R. Gillies ◽  
Randal Martin
Keyword(s):  
Air Quality ◽  
Air Temperature ◽  
Daily Maximum ◽  
Horizontal Distance ◽  
Climate Conditions ◽  
Air Temperatures ◽  
Narrow Valley ◽  
Northern Utah ◽  
Temperature Inversions

AbstractBecause of the geography of a narrow valley and surrounding tall mountains, Cache Valley (located in northern Utah and southern Idaho) experiences frequent shallow temperature inversions that are both intense and persistent. Such temperature inversions have resulted in the worst air quality in the nation. In this paper, the historical properties of Cache Valley’s winter inversions are examined by using two meteorological stations with a difference in elevation of approximately 100 m and a horizontal distance apart of ~4.5 km. Differences in daily maximum air temperature between two stations were used to define the frequency and intensity of inversions. Despite the lack of a long-term trend in inversion intensity from 1956 to present, the inversion frequency increased in the early 1980s and extending into the early 1990s but thereafter decreased by about 30% through 2013. Daily mean air temperatures and inversion intensity were categorized further using a mosaic plot. Of relevance was the discovery that after 1990 there was an increase in the probability of inversions during cold days and that under conditions in which the daily mean air temperature was below −15°C an inversion became a certainty. A regression model was developed to estimate the concentration of past particulate matter of aerodynamic diameter ≤ 2.5 μm (PM2.5). The model indicated past episodes of increased PM2.5 concentrations that went into decline after 1990; this was especially so in the coldest of climate conditions.

scholarly journals Validation of a Commercial System for Remote Estimation of Wetness Duration

Plant Disease ◽  
1997 ◽  
Vol 81 (7) ◽  
pp. 825-829 ◽  
Author(s):  
Mark L. Gleason ◽  
Sharon K. Parker ◽  
Ron E. Pitblado ◽  
Richard X. Latin ◽  
Donna Speranzini ◽  
...  
Keyword(s):  
Air Temperature ◽  
Decision Rules ◽  
Simulation Models ◽  
The United States ◽  
Error Rates ◽  
Mean Values ◽  
Air Temperatures ◽  
Mathematical Simulations ◽  
Remote Estimation ◽  
Period Duration

To assess the accuracy of remote, real-time mathematical simulations of wetness duration and air temperature, hourly measurements of wetness duration and air temperature at 18 sites in the United States and Canada from May to September 1995 were compared with simulations for these sites provided by SkyBit, Inc. SkyBit simulations of mean, maximum, and minimum daily air temperatures varied from on-site measurements by less than 0.7°C but underestimated the duration of wet periods by an average of 3.4 h/day. At five of six stations tested, SkyBit underestimates of wetness duration were significantly (P < 0.01) larger on days when no rain was measured than on rainy days, indicating that simulations of dew-period duration were much less accurate than simulations of rain-period duration. The vast majority of hours SkyBit misclassified as dry occurred either when entire wet periods were missed (59.3%) or when the onset of a wet period was detected late (28.4%). The results suggest that revision of SkyBit wetness-simulation models should focus on reducing error rates during dew events. In simulations using two disease-warning models, TOM-CAST and Melcast, with mean values of measured and SkyBit-simulated wetness duration, SkyBit-simulated values resulted in fewer and later fungicide spray advisories than did measured values. The magnitude of these impacts varied with the magnitude of the simulation errors and with differences in the models' decision rules.

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